Name: Coastal Wetland Catchment SumRel Stress Index
Display Field: region
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: Index representing land cover, population density, point source discharge, and road density. We evaluated a number of normalizing transformations for each variable, including log, ln, and arcsine transformations. The use of high-resolution watersheds resulted in a large number of zeros (i.e. non-occurrence of the stressor) for many of the variables. The best results were obtained using a log10 transformation of non-zero values. Each of the five variables data values (x) were transformed to log10 (x), using the minimum non-zero value of x to replace zero values. These transformed (x') values were then standardized, (x'-m)/s, with m and s being the mean and standard-deviation for all x', respectively. These standardized values (x'') were then normalized, (x''-min)/(max-min), with min and max being the minimum and maximum for all x'', respectively. Finally the five x'' values for each variable in each watershed were summed and the summed values normalized again to give a single number - SUMREL - for each watershed. SUMREL ranges from 0.0-1.0, with 1.0 representing the maximum composite stress within a geographic coverage of interest. Note that this design allows stressor scores to be calculated for any given spatial extent - from local watersheds to an ecoregion, lake, or basin.
Name: Coastal Wetland Catchment Total Phosphorus Load (kg) 12 year period
Display Field: GNIS_name
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: Total Phophorus load (kg) entering the Great Lakes over a 12 year period coming from land in each delineated by coastal wetland catchments
Name: Coastal Wetland Catchment Total Phosphorus (kg) per Square Kilometer
Display Field: GNIS_name
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: Total Phophorus load (kg) entering the Great Lakes during the summer over a 12 year period summarized by coastal wetland catchments, and normalized by area.